DNA

• DNA is a molecule that carries a genetic code that makes up an individual; it controls proteins that form our bodies and help us function
• DNA is self replicating
• A gene is a section of DNA that codes for one protein or part of a protein
• Genes are made from nucleotides, which contain nitrogenous bases (adenine, thymine, cytosine, guanine)
• DNA is made up of two nucleotides held together by hydrogen bonds
• Nucleotides are building block of DNA made up of 3 parts: nitrogen base (base), deoxyribose (sugar molecule), phosphate molecule
• There are 4 types of bases: adenine, thymine, guanine and cytosine
• adenine and thymine are complementary bases, and guanine and cytosine are complementary bases
• A polynucleotide chain is when 2 Nucleotides join together to form a nucleic acid (DNA)
• Polynucleotide chain is joined together by the sugar and phosphate molecules in nucleotide (this forms sugar-phosphate backbone)
• The double helix of a DNA is formed when the sugar-phosphate backbone of one nucleic acid chain connects with the phosphate backbone of a second nucleic acid chain
• Insides of double helix is the bonds of complementary nitrogen bases, bonded by hydrogen bonds
• The DNA can be found in the nucleus of a cell
• Chromosome = thread like structure made up of DNA
• Genes are sections of DNA that code for specific proteins
• Chromosome = molecule of DNA (DNA helix)
• structure of nucleotide chain

  A) nucleotide

  B) sugar

  C) hydrogen bond

  D) nitrogen base

  E) phosphate group

  F) sugar phosphate backbone

  
• Chromosomes can be found in the nucleus of a cell
• Chromosomes are DNA wrapped around proteins
• A karyotype is a Picture of chromosomes, arranged from largest to smallest
• The last chromosome is what determines gender: XX=female, XY=male
• Females always pass X on to their offspring, Males pass either X or Y, determining the gender of the offspring
• What to look for in karyotype:

  -              Sets of 2

  -              Similar length

  -              Corresponding stripes/colours

       
• Genes are sections in chromosomes that contains information for a specific characteristic or trait
• The sequence of bases in a nucleotide is what determines one gene different from the other
• Largest to smallest: Cell – nucleus – chromosome – DNA – gene – nucleotides 
• Chromosome = molecule of DNA (DNA helix)
• Chromosomes can be a single helix, or a pair